Storage medium for use with a three-dimensional map display device

ABSTRACT

A model transforming data generating portion  4  extracts parameter data corresponding to a given road area from two-dimensional map data in a two-dimensional map data storage portion  3.  Subsequently, the model transforming data generating portion  4  reads out pattern data corresponding to the specified road area from a pattern model storage portion  5  and generates model transforming data. An image data generating portion  6  transforms a corresponding three-dimensional map display model by using the generated model transforming data to generate three-dimensional image data. The generated three-dimensional image data is given to and displayed in a display  7.  The operator operates an input portion  2  on the basis of the contents displayed in the display  7  to correct the generated model transforming data.

TECHNICAL FIELD

[0001] The present invention relates to three-dimensional map displaydevices, and more particularly to a device for simply displaying athree-dimensional configuration of a target area on a map.

BACKGROUND ART

[0002] A conventional car navigation system generally navigates alongthe route by displaying a two-dimensional map. In a case where a road isoverlaying on another in parallel as shown on a display navigating avicinity of freeway entrances and exits, however, a two-dimensional mapwithout a longitudinal representation often puzzles a driver as to whichway to go. Also, as to a multi-level intersection of a ordinary-typeroad to be navigated, when the display navigates to turn right afterpassing the multi-level intersection, it is difficult for the driver toinstantaneously understand the navigated route as a conventional carnavigation system does not represent the route stereoscopically.

[0003] Recently, various car navigation systems are being developed todisplay a map in a three-dimensional manner. Conventionally, when a mapis three-dimensionally displayed, width and height information ismanually provided to data about roads on a two-dimensional map inadvance so as to generate three-dimensional polygon data from the mapdata having the information provided, and then the three-dimensionalpolygon data is stored in a map storage medium (CD-ROM, DVD, etc.). Whena vehicle reaches a point to be navigated, a car navigation system inwhich this map storage medium is provided reads out correspondingthree-dimensional polygon data from the map storage medium and displaysa three-dimensional image.

[0004] The conventional system, however, requires width and heightinformation to be added to every piece of road data on a two-dimensionalmap, which considerably complicates the processing. Further, it requirespreparation such as measurements, and the like. Moreover, sincetwo-dimensional map data contains a large amount of information which donot conform to the real-world road locations, an accuracy of athree-dimensional map obtained through such data on the two-dimensionalmap data is poor, which confuses the driver more. Information on rodelocations on a two-dimensional map may be corrected, or configurationdata on a completed three-dimensional map may be corrected with a CADtool, and the like in order to obtain a desired three-dimensional map.It will require a large number of additional processing steps. Further,since an accuracy of the conventional polygon automatic generatingalgorithm is poor, parts separated into small links andcoupling/branching parts between two road links differing in widthcannot be smoothly connected. That is to say, the polygon data does notcoincide with the real-world road configuration, which will ratherreduce the safety.

[0005] Moreover, in the conventional system, the three-dimensionalpolygon data itself is stored in a map storage medium (CD-ROM, DVD,etc.), and therefore the amount of map data to be stored is too large tothree-dimensionally display many areas. To solve such an inconvenience,two-dimensional map data containing added width and height informationmay be stored in the map storage medium, in which case a car navigationsystem carried on a vehicle creates the three-dimensional polygon data.However, this method largely increases the load on a CPU of the carnavigation system, resulting in another problem that the map cannot bescrolled at high speed.

[0006] Accordingly, an object of the present invention is to provide athree-dimensional map display method and a device which can easily andsimply display the three-dimensional configuration of target areas on amap, with a largely reduced amount of data stored in a storage medium,and a device for creating data used in the method and device.

DISCLOSURE OF THE INVENTION

[0007] The present invention has the following features to achieve theobject above.

[0008] A first aspect of the invention is directed to a device forcreating model transforming data used to transform a three-dimensionalmap display model, wherein a three-dimensional configuration of a givenpart on a map is classified in advance into a plurality of patterns anda standard three-dimensional map display model is prepared for eachpattern, and the model transforming data creating device comprises:

[0009] a two-dimensional map data storage portion for storingtwo-dimensional map data;

[0010] a parameter data extracting portion for extracting parameter datacorresponding to the given part from the two-dimensional map data storedin the two-dimensional map data storage portion;

[0011] a parameter data analyzing portion for analyzing the parameterdata extracted by the parameter data extracting portion to generate themodel transforming data; and

[0012] a storage portion for storing the model transforming datagenerated by the parameter data analyzing portion.

[0013] As stated above, according to the first aspect, instead of thethree-dimensional image data itself, the model transforming data fortransforming a previously prepared three-dimensional map display modelinto a desired form is generated as data for obtaining athree-dimensional image of a given part on a map, and then the data forthree-dimensional map display can be provided in an extremely compressedform as compared with conventional ones.

[0014] According to a second aspect which depends on the first aspect,

[0015] the model transforming data creating device further comprises apattern model storage portion for storing pattern data defining sorts ofparameters required when transforming the three-dimensional map displaymodel for each pattern,

[0016] wherein the parameter data analyzing portion comprises:

[0017] a pattern data reading portion for reading the pattern datacorresponding to the given part from the pattern model storage portion;and

[0018] a data converting portion for converting the parameter dataextracted by the parameter data extracting portion into the modeltransforming data on the basis of the pattern data read out by thepattern data reading portion.

[0019] As stated above, according to the second aspect, the parameterdata is converted into the model transforming data on the basis of thepattern data, and more detailed model transforming data can be createdas compared with the case in which the model transforming data iscreated from only the parameter data.

[0020] According to a third aspect which depends on the second aspect,

[0021] the pattern data reading portion comprises a pattern. determiningportion for determining the pattern on the basis of the parameter dataextracted by the parameter data extracting portion and reading out thepattern data corresponding to the determined pattern from the patternmodel storage portion.

[0022] As stated above, according to the third aspect, the parameterdata can be automatically read from the parameter data storage portionwithout requiring manual operation.

[0023] According to a fourth aspect which depends on the third aspect,

[0024] the pattern determining portion comprises:

[0025] a branching part road attribute deciding portion for decidingattributes of roads around a branching point on the basis of theparameter data extracted by the parameter data extracting portion; and

[0026] a branch type deciding portion for deciding the type of thebranching on the basis of the road attributes decided by the branchingpart road attribute deciding portion to determine the pattern.

[0027] As stated above, according to the fourth aspect, the pattern isdetermined according to the road attributes at a branching pointespecially requiring three-dimensional display, which enables patterndiscrimination more conforming with the real-world road configuration.

[0028] According to a fifth aspect which depends on the fourth aspect,

[0029] the parameter data analyzing portion further comprises:

[0030] a parameter data classifying portion for classifying theparameter data according to road function on the basis of the patterndetermined by the pattern determining portion; and

[0031] a data integrating portion for integrating the parameter dataclassified by the parameter data classifying portion within eachclassified group, and

[0032] the data converting portion converts the parameter dataintegrated by the data integrating portion into the model transformingdata.

[0033] As stated above, according to the fifth aspect, not the mereparameter data extracted from the two-dimensional map data but theintegrated parameter data is converted into the model transforming data,so that a three-dimensional map display model with a less number ofconnected portions can be adopted to provide a beautifulthree-dimensional image, and the finally obtained three-dimensionalimage can be simplified on the basis of the road function to providenavigation display easy to understand for the user.

[0034] According to a sixth aspect which depends on the fifth aspect,

[0035] the parameter data classifying portion comprises:

[0036] a link tracing portion for tracing a desired link on the basis ofthe two-dimensional parameter data extracted by the two-dimensionalparameter data extracting portion and temporarily storing and holdingdata of the traced link; and

[0037] a link data classifying portion for classifying the link datastored and held in the link tracing portion on the basis of the patterndetermined by the pattern determining portion.

[0038] As stated above, according to the sixth aspect, the amount ofparameter data as the source data for classification can be reduceddepending on the condition for tracing links, and then the classifyingoperation can be performed at high speed.

[0039] According to a seventh aspect which depends on the second aspect,

[0040] the pattern data reading portion reads the pattern datacorresponding to a pattern indicated by an operator from the patterndata storage portion.

[0041] According to an eighth aspect which depends on the second aspect,

[0042] the data converting portion obtains values of part of theparameters defined by the pattern data read by the pattern data readingportion directly from the parameter data extracted by the parameter dataextracting portion and obtains remaining parameter values by inferenceprocessing.

[0043] As stated above, according to the eight aspect, parameterswanting when generating the model transforming data can be automaticallyobtained by inference.

[0044] According to a ninth aspect which depends on the second aspect,

[0045] the data converting portion obtains values of part of theparameters defined by the pattern data read by the pattern data readingportion directly from the parameter data extracted by the parameter dataextracting portion and obtains remaining parameter values through aninstruction from an operator.

[0046] According to a tenth aspect which depends on the first aspect,

[0047] the model transforming data creating device further comprises:

[0048] an image data generating portion for generating three-dimensionalimage data by applying the model transforming data generated by theparameter data analyzing portion to the corresponding three-dimensionalmap display model and transforming the three-dimensional map displaymodel; and

[0049] a display portion for displaying the three-dimensionalconfiguration of the given part on the basis of the three-dimensionalimage data generated by the image data generating portion.

[0050] As stated above, according to the tenth aspect, since thethree-dimensional configuration obtained on the basis of the generatedmodel transforming data is displayed in a real-time manner, it is easyto see whether desired model transforming data has been obtained.

[0051] According to an eleventh aspect which depends on the tenthaspect,

[0052] the model transforming data creating device further comprises amodel transforming data correcting portion for correcting the modeltransforming data generated by the parameter data analyzing portion inresponse to an instruction from an operator.

[0053] As stated above, according to the eleventh aspect, the modeltransforming data can be corrected and the corrected three-dimensionalconfiguration can be displayed, and thus the correcting operation can beachieved easily.

[0054] According to a twelfth aspect which depends on the first aspect,

[0055] the parameter data extracting portion extracts the parameter dataof a part indicated by an operator from the two-dimensional map data.

[0056] According to a thirteenth aspect which depends on the firstaspect,

[0057] the parameter data extracting portion extracts the parameter dataof a part which conforms with a previously set condition from thetwo-dimensional map data.

[0058] As stated above, according to the thirteenth aspect, the part tobe three-dimensionally displayed on a map can be automatically specifiedto extract parameters.

[0059] According to a fourteenth aspect, a device for creatingthree-dimensional polygon data used to display a three-dimensionalconfiguration of a given part on a map comprises:

[0060] a two-dimensional map data storage portion for storingtwo-dimensional map data;

[0061] a parameter data extracting portion for extracting parameter datacorresponding to the given part from the two-dimensional map data storedin the two-dimensional map data storage portion;

[0062] a parameter data analyzing portion for analyzing the parameterdata extracted by the parameter data extracting portion to generatemodel transforming data;

[0063] a three-dimensional polygon data generating portion forgenerating the three-dimensional polygon data by applying the modeltransforming data generated by the parameter data analyzing portion to acorresponding three-dimensional map display model to transform thethree-dimensional map display model; and

[0064] a three-dimensional polygon data storage portion for storing thethree-dimensional polygon data generated by the three-dimensionalpolygon data generating portion.

[0065] As stated above, according to the fourteenth aspect, thethree-dimensional polygon data is obtained by transforming a previouslyprepared three-dimensional map display model, so that the computationfor generating the three-dimensional polygon data can be simplified.

[0066] According to a fifteenth aspect, a device for creatingthree-dimensional image data used to display a three-dimensionalconfiguration of a given part on a map comprises:

[0067] a two-dimensional map data storage portion for storingtwo-dimensional map data;

[0068] a parameter data extracting portion for extracting parameter datacorresponding to the given part from the two-dimensional map data storedin the two-dimensional map data storage portion;

[0069] a parameter data analyzing portion for analyzing the parameterdata extracted by the parameter data extracting portion to generatemodel transforming data;

[0070] a three-dimensional polygon data generating portion forgenerating three-dimensional polygon data by applying the modeltransforming data generated by the parameter data analyzing portion to acorresponding three-dimensional map display model to transform thethree-dimensional map display model;

[0071] a three-dimensional image data generating portion for generatingthe three-dimensional image data on the basis of the three-dimensionalpolygon data generated by the three-dimensional polygon data generatingportion; and

[0072] a three-dimensional image data storage portion for storing thethree-dimensional image data generated by the three-dimensional imagedata generating portion.

[0073] As stated above, according to the fifteenth aspect, thethree-dimensional image data is generated from the three-dimensionalpolygon data obtained by transforming a previously preparedthree-dimensional map display model, so that the computation forgenerating the three-dimensional image data can be simplified.

[0074] A sixteenth aspect is directed to a three-dimensional map displaydevice for displaying a three-dimensional configuration of a given parton a map,

[0075] wherein the three-dimensional configuration of the given part onthe map is classified in advance into a plurality of patterns and astandard three-dimensional map display model is prepared for eachpattern, and the three-dimensional map display device comprises:

[0076] a two-dimensional map data storage portion for storingtwo-dimensional map data;

[0077] a parameter data extracting portion for extracting parameter datacorresponding to the given part from the two-dimensional map data storedin the two-dimensional map data storage portion:

[0078] a parameter data analyzing portion for analyzing the parameterdata extracted by the parameter data extracting portion to generatemodel transforming data used to transform the three-dimensional mapdisplay model:

[0079] an image data generating portion for generating three-dimensionalimage data by applying the model transforming data generated by theparameter data analyzing portion to the corresponding three-dimensionalmap display model to transform the three-dimensional map display modelinto a desired form: and

[0080] a display portion for displaying the three-dimensionalconfiguration of the given part on the basis of the three-dimensionalimage data generated by the image data generating portion.

[0081] As stated above, according to the sixteenth aspect, the mapconfiguration is classified into a plurality of patterns and a standardthree-dimensional map display model prepared for each pattern istransformed to obtain a three-dimensional image, which enablesthree-dimensional display more fitted to the object of the navigation(that is to say, to enable clear understanding of the correspondencebetween real-world roads and navigated routes) as compared with theconventional system in which a three-dimensional image is obtaineddirectly from two-dimensional map data with added width and heightinformation. That is to say, according to the sixteenth aspect, thebasic configuration of roads is previously prepared in the form of athree-dimensional map display model, and therefore the relation amongroads, such as how roads are connected to one another or branched, isnot largely changed even when the three-dimensional map display model islargely transformed. Accordingly, errors in some degrees existing on thetwo-dimensional map data are automatically corrected at the time whenthe pattern of the specified road part is determined, which reduces apossibility of displaying errors far apart from the original object ofthe navigation. Also, according to the sixteenth aspect, it is notnecessary to perform all the steps for calculating and generating thethree-dimensional image data, but it can be generated by just performingthe calculation of transforming a previously defined three-dimensionalmap display model on the basis of the model transforming data, and theamount of calculation can be largely reduced as compared withconventional case. This enables high-speed picture drawing processing.Further, according to the sixteenth aspect, since the model transformingdata is generated within the three-dimensional map display device, themap storage medium can be used to store the two-dimensional map dataonly, and the device can work with almost the same amount of previouslystored map data as a conventional map display device displaying atwo-dimensional map.

[0082] According to a seventeenth aspect which depends on the sixteenthaspect,

[0083] the three-dimensional map display device further comprises apattern model storage portion for storing pattern data defining sorts ofparameters required when transforming the three-dimensional map displaymodel for each pattern, and

[0084] the parameter data analyzing portion comprises:

[0085] a pattern data reading portion for reading out the pattern datacorresponding to the given part from the pattern model storage portion;and

[0086] a data converting portion for converting the parameter dataextracted by the parameter data extracting portion into the modeltransforming data on the basis of the pattern data read by the patterndata reading portion.

[0087] As stated above, according to the seventeenth aspect, theparameter data is converted into the model transforming data on thebasis of the pattern data, and more detailed model transforming data canthus be created as compared with a case in which the model transformingdata is created from only the parameter data.

[0088] According to an eighteenth aspect which depends on theseventeenth aspect,

[0089] the pattern data reading portion comprises a pattern determiningportion for determining the pattern on the basis of the parameter dataextracted by the parameter data extracting portion and reading out thepattern data corresponding to the determined pattern from the patternmodel storage portion.

[0090] As stated above, according to the eighteenth aspect, theparameter data can be automatically read out from the parameter datastorage portion without through manual operation.

[0091] According to a nineteenth aspect which depends on the eighteenthaspect,

[0092] the pattern determining portion comprises:

[0093] a branching part road attribute deciding portion for decidingattributes of roads around a branching point on the basis of theparameter data extracted by the parameter data extracting portion; and

[0094] a branch type deciding portion for deciding the type of thebranching on the basis of the road attributes decided by the branchingpart road attribute deciding portion to determine the pattern.

[0095] As stated above, according to the nineteenth aspect, the patternis determined in accordance with road attributes at a branching pointespecially requiring three-dimensional display, so that the pattern canbe determined in a manner more fitted to the real-world roadconfiguration.

[0096] According to a twentieth aspect which depends on the nineteenthaspect,

[0097] the parameter data analyzing portion further comprises:

[0098] a parameter data classifying portion for classifying theparameter data according to road function on the basis of the patterndetermined by the pattern determining portion; and

[0099] a data integrating portion for integrating the parameter dataclassified by the parameter data classifying portion within eachclassified group; and

[0100] the data converting portion converts the parameter dataintegrated by the data integrating portion into the model transformingdata.

[0101] As stated above, according to the twentieth aspect, not the mereparameter data extracted from the two-dimensional map data but theintegrated parameter data is converted into the model transforming data,so that a three-dimensional map display model with a less number ofconnected portions can be adopted to provide a beautifulthree-dimensional image, and the finally obtained three-dimensionalimage can be simplified on the basis of road function to providenavigation display easy to understand for the user.

[0102] According to a twenty-first aspect which depends on the twentiethaspect,

[0103] the parameter data classifying portion comprises:

[0104] a link tracing portion for tracing a desired link on the basis ofthe two-dimensional parameter data extracted by the two-dimensionalparameter data extracting portion and temporarily storing and holdingdata of the traced link; and

[0105] a link data classifying portion for classifying the link datastored and held in the link tracing portion on the basis of the patterndetermined by the pattern determining portion.

[0106] As stated above, according to the twenty-first aspect, the amountof the parameter data as the source data for classification can bereduced depending on the condition used when tracing links, and thecomputation for classification can be performed at high speed.

[0107] According to a twenty-second aspect which depends on theseventeenth aspect,

[0108] the data converting portion obtains values of part of theparameters defined by the pattern data read by the pattern data readingportion directly from the parameter data extracted by the parameter dataextracting portion and obtains remaining parameter values by inference.

[0109] As stated above, according to the twenty-second aspect,parameters wanting in generating the model transforming data can beautomatically obtained by inference.

[0110] According to a twenty-third aspect which depends on thetwenty-second aspect,

[0111] the three-dimensional map display device is installed in a carnavigation device for navigating a vehicle on the map.

[0112] A twenty-fourth aspect is directed to a three-dimensional mapdisplay device for displaying a three-dimensional configuration of agiven part on a map,

[0113] wherein the three-dimensional configuration of the given part onthe map is classified in advance into a plurality of patterns and astandard three-dimensional map display model is prepared for eachpattern, and the three-dimensional map display device comprises:

[0114] a model transforming data storage portion for storing modeltransforming data for transforming the three-dimensional map displaymodel;

[0115] an image data generating portion for generating three-dimensionalimage data by reading out the model transforming data corresponding tothe given part and applying the model transforming data to thecorresponding three-dimensional map display model to transform thethree-dimensional map display model into a desired form; and

[0116] a display portion for displaying the three-dimensionalconfiguration of the given part on the basis of the three-dimensionalimage data generated by the image data generating portion.

[0117] As stated above, according to the twenty-fourth aspect, the mapconfiguration is classified into a plurality of patterns and a standardthree-dimensional map display model prepared for each pattern istransformed to obtain a three-dimensional image, which enablesthree-dimensional display more fitted to the object of the navigation(that is to say, to understand a correspondence between real-world roadsand navigated routes in a clear manner) as compared with theconventional system in which a three-dimensional image is obtaineddirectly from two-dimensional map data with added width and heightinformation. That is to say, according to the twenty-fourth aspect, thebasic configuration of roads is previously prepared as athree-dimensional map display model, and therefore the relation amongroads, such as how roads are connected to one another or branched, isnot largely changed even when the three-dimensional map display model islargely transformed. Accordingly, errors in some degrees existing on thetwo-dimensional map data are automatically corrected at the time whenthe pattern of the specified road part is determined, which reduces aprobability of displaying errors far apart from the original object ofthe navigation. Also, according to the twenty-fourth aspect, it is notnecessary to perform all the steps for calculating and generating thethree-dimensional image data, but it can be generated by just performingthe calculation of transforming a previously defined three-dimensionalmap display model on the basis of the model transforming data, and theamount of calculation can be largely reduced as compared with aconventional case. This enables high-speed picture drawing processing.Further, according to the twenty-fourth aspect, the device stores themodel transforming data extremely compressed as compared with thethree-dimensional polygon data and three-dimensional image data, so thatthe amount of previously stored map data (data required to display athree-dimensional map) can be considerably reduced, as compared with aconventional map display device displaying a three-dimensional map.

[0118] According to a twenty-fifth aspect which depends on thetwenty-fourth aspect,

[0119] the three-dimensional map display device is installed in a carnavigation device for navigating a vehicle on the map.

[0120] A twenty-sixth aspect is directed to a method for displaying athree-dimensional configuration of a given part on two-dimensional mapdata, the method comprising the steps of:

[0121] classifying in advance the three-dimensional configuration of thegiven part into a plurality of patterns and preparing in advance astandard three-dimensional map display model for each pattern;

[0122] extracting parameter data corresponding to the given part fromthe two-dimensional map data;

[0123] generating model transforming data from the extracted parameterdata; and

[0124] applying the model transforming data to the correspondingthree-dimensional map display model to transform the three-dimensionalmap display model into a desired form, thereby obtaining athree-dimensional image of the given part.

[0125] As stated above, according to the twenty-sixth aspect, the mapconfiguration is classified into a plurality of patterns and a standardthree-dimensional map display model prepared for each pattern istransformed to obtain a three-dimensional image, which enablesthree-dimensional display more fitted to the object of the navigation(that is to say, to understand a correspondence between real-world roadsand navigated roads in a clear manner) as compared with the conventionalsystem in which a three-dimensional image is obtained directly fromtwo-dimensional map data with added width and height information. Thatis to say, according to the twenty-sixth aspect, the basic configurationof roads is previously prepared as a three-dimensional map display modeland therefore the relation among roads, such as the configuration ofconnections and branches of roads, is not largely changed even when thethree-dimensional map display model is largely transformed. Accordingly,errors in some degrees existing on the two-dimensional map data areautomatically corrected at the time when the pattern of the specifiedroad part is determined, which reduces a possibility of displayingerrors far apart from the original object of the navigation. Also,according to the twenty-sixth aspect, it is not necessary to perform allthe steps for calculating and generating the three-dimensional imagedata, but it can be generated by just performing the calculation oftransforming a previously defined three-dimensional map display model onthe basis of the model transforming data, and the amount of calculationcan be largely reduced as compared with conventional devices. Thisenables high-speed picture drawing processing.

[0126] A twenty-seventh aspect is directed to a storage medium used in athree-dimensional map display device in which a three-dimensionalconfiguration of a given part on two-dimensional map data is classifiedin advance into a plurality of patterns and a standard three-dimensionalmap display model is prepared in advance for each pattern, and thethree-dimensional map display model is transformed into a desired formto generate and display three-dimensional image data of the given part,

[0127] wherein the storage medium contains model transforming data fortransforming the three-dimensional map display model into the desiredform in correspondence with each road part to be three-dimensionallydisplayed.

[0128] As stated above, according to the twenty-seventh aspect, data forthree-dimensional map display can be stored in an extremely compressedform.

BRIEF DESCRIPTION OF THE DRAWINGS

[0129]FIG. 1 is a block diagram showing the structure of a modeltransforming data creating device according to an embodiment of thepresent invention.

[0130]FIG. 2 is a block diagram showing the more detailed structure ofthe model transforming data generating portion 4 shown in FIG. 1.

[0131]FIG. 3 is a block diagram showing the more detailed structure ofthe parameter data analyzing portion 43 shown in FIG. 2.

[0132]FIG. 4 is a flowchart used to explain the operation of the modeltransforming data creating device 1 shown in FIG. 1.

[0133]FIG. 5 is a diagram showing an example of two-dimensionalparameter data extracted from two-dimensional map data.

[0134]FIG. 6 is a diagram showing the map parameters of FIG. 5 in a formvisualized as a two-dimensional map.

[0135]FIG. 7 is a flowchart showing the more detailed operation of thesubroutine step S5 shown in FIG. 4.

[0136]FIG. 8 is a diagram showing examples of types of branching roads.

[0137]FIG. 9 is a diagram showing an example of three-dimensional mapdisplay model pattern used in the case in which a road on the groundbranches out into an elevated road and a side pass.

[0138]FIG. 10 is a diagram showing an example of three-dimensional mapdisplay model pattern used in the case in which a road on the groundbranches out into an underpass and a side pass.

[0139]FIG. 11 is a diagram showing an example of three-dimensional mapdisplay model pattern used in the case in which an elevated roadbranches out into an elevated road and a side pass.

[0140]FIG. 12 is a diagram showing an example of pattern data stored inthe pattern model storage portion 5 of FIG. 1.

[0141]FIG. 13 is a diagram showing an example of parameter dataclassified according to road function.

[0142]FIG. 14 is a flowchart showing the more detailed operation of thesubroutine step S6 shown in FIG. 4.

[0143]FIG. 15 is a diagram showing an example of a two-dimensional map.

[0144]FIG. 16 is a diagram showing an example of results obtained bytracing links.

[0145]FIG. 17 is a diagram showing an example of results obtained bystoring the link data of the traced links.

[0146]FIG. 18 is a diagram showing an example of results obtained byclassifying the links according to road function.

[0147]FIG. 19 is a diagram showing an example of parameter datagenerated by integrating the classified data.

[0148]FIG. 20 is a diagram showing the parameter data of FIG. 19visualized as a two-dimensional map.

[0149]FIG. 21 is a diagram showing an example of pattern data in whichparameters are set (model transforming data).

[0150]FIG. 22 is a diagram showing examples of shapes of roads whichbelong to a first category.

[0151]FIG. 23 is a diagram showing examples of shapes of roads whichbelong to a second category.

[0152]FIG. 24 is a diagram showing examples of shapes of roads whichbelong to a third category.

[0153]FIG. 25 is a diagram showing an example of display of athree-dimensional map generated by using the model transforming datashown in FIG. 21.

[0154]FIG. 26 is a block diagram showing the more detailed structure ofthe image data generating portion 6 shown in FIG. l.

[0155]FIG. 27 is a block diagram showing the more detailed structure ofthe three-dimensional polygon data generating portion 61 shown in FIG.26.

[0156]FIG. 28 is a diagram showing an example of contents of parametersand default values thereof stored in the configuration attribute storageportion 613 of FIG. 27.

[0157]FIG. 29 is a flowchart showing the operation of thethree-dimensional polygon data generating portion 61 shown in FIG. 26.

[0158]FIG. 30 is a schematic diagram used to explain the operation ofthe model transforming data analyzing portion 611 shown in FIG. 27.

[0159]FIG. 31 is a schematic diagram used to explain the operation ofthe three-dimensional polygon data synthesizing portion 612 shown inFIG. 27.

[0160]FIG. 32 is a diagram showing the outline of the processing offunction FUNC1.

[0161]FIG. 33 is an image diagram showing three-dimensional polygon datagenerated by the function FUNC1.

[0162]FIG. 34 is a diagram showing the outline of the processing offunction FUNCB1.

[0163]FIG. 35 is a diagram showing an example of results obtained by theprocessing of the function FUNCB1.

[0164]FIG. 36 is an image diagram showing three-dimensional polygon datagenerated by the function FUNCB1.

[0165]FIG. 37 is a block diagram showing the structure of a navigationdevice according to an embodiment of the present invention.

[0166]FIG. 38 is a block diagram showing the greater details of thestructure of the navigating portion 14 shown in FIG. 37.

[0167]FIG. 39 is a flowchart showing the operation of the navigatingportion 14 shown in FIG. 37.

[0168]FIG. 40 is a block diagram showing the greater details of thestructure of the three-dimensional map display portion 143 shown in FIG.38.

[0169]FIG. 41 is a flowchart showing the operation of thethree-dimensional map display portion 143 shown in FIG. 40.

[0170]FIG. 42 is a block diagram showing the structure of athree-dimensional map display portion 143 having a communication device.

[0171]FIG. 43 is a block diagram showing another structure of thethree-dimensional map display portion 143 shown in FIG. 38.

BEST MODE FOR CARRYING OUT THE INVENTION

[0172] Before describing embodiments of the present invention in detail,the basic idea of the present invention will now be described tofacilitate understanding of the invention.

[0173] The present invention was made to enable three-dimensionaldisplay of a given road area on a map. As is well known for aconventional car navigation system of a general type, when a navigatedroute comes closer to a junction or a point to turn right or left,configurations of roads around the point are displayed in an enlargedmanner. A typical application of the present invention is tothree-dimensionally display the enlarged configurations. The presentinvention is also applicable to a system in which navigated roads areall three-dimensionally displayed.

[0174] In the present invention, configuration of roads to bethree-dimensionally displayed are previously classified into somepatterns each including similar types. For example, configurations ofroads are classified into a multi-level intersection, underpass,junction, elevated road, freeway, and the like. The present inventionpreviously prepares a standard three-dimensional map display model foreach of the classified patterns, and creates model transforming datafrom parameters extracted from two-dimensional map data and transformsthe corresponding three-dimensional map display model into desired formby applying the model transforming data. Thus, a three-dimensional imagecorresponding to the given road area is obtained.

[0175] Since a conventional system obtains a three-dimensional image byhandling two-dimensional map data containing additional width and heightinformation as three-dimensional coordinate data, it completely neglectshow the roads are connected to one another or branched. Accordingly,when the two-dimensional map data contains errors, the errors aredirectly incorporated into the tree-dimensional image. For example, anelevated road may be discontinued halfway or branched roads running inparallel may be largely curved.

[0176] On the other hand, the present invention previously classifiesroad configurations into a plurality of patterns, prepares a standardthree-dimensional map display model for the individual patterns, andtransforms the three-dimensional map display models to obtainthree-dimensional images, which enables three-dimensional display morefitted to the original object of the car navigation (that is to say, tounderstand a correspondence between real-world roads and a navigatedroute in a clear manner) as compared with the conventional system inwhich three-dimensional image is obtained directly from two-dimensionalmap data having width and height information added. That is, in thepresent invention, basic configurations of roads are previously preparedin the form of three-dimensional map display models in athree-dimensional image data generating algorithm, and therefore basicrelation among roads, i.e., how the roads are connected to one anotheror branched, is not largely changed even when the three-dimensional mapdisplay models are largely transformed. Accordingly, errors in somedegrees existing on the two-dimensional map data are automaticallycorrected when a configuration of a road to be three-dimensionallydisplayed is determined to which pattern it belongs, which reduces aprobability of displaying errors far apart from the original object ofthe navigation system.

[0177] On the other hand, since the present inventionthree-dimensionally displays the map configuration in deformed(simplified or exaggerated) manner, the displayed three-dimensionalimage does not completely conform with the real-world roadconfiguration, unlike the conventional system in which two-dimensionalmap data having width and height information added is handled asthree-dimensional coordinate data. In other words, as compared with theconventional system, the present invention displays a three-dimensionalmap in a form closer to animated cartoon. However, when a vehicle isnavigated, it is not necessary that the displayed three-dimensional mapcompletely corresponds to the real-world road configuration. Incar-navigation, no problem arises even if the angles of slopes ofelevated roads and scales of roads differ from the actual values. Theobject of the car-navigation can be achieved if the display can showwhether roads are rising or descending and how many lanes they have, atleast. That is to say, the object of car-navigation can be achieved ifthe display shows enough information for a driver to clearly understandthe correspondence between real-world roads and the displayednavigation, such as the configuration of branching roads, verticalrelation between roads. Accordingly, just transforming a previouslyprepared three-dimensional map display model can sufficiently achievethe object of the car-navigation. Conversely, such deformed display asis made in the present invention is easier for the driver to understand.

[0178] As stated above, it is not necessary to accurately transformprepared three-dimensional map display models so as to completelycorrespond to the real-world road configuration, and the object of thenavigation can be achieved by transforming the three-dimensional mapdisplay models to such an extent that the object of the car-navigationis not impeded. This means that the number of parameters given to thethree-dimensional map display models can be reduced. Further, when thepresent invention is applied to a car navigation system, not thethree-dimensional image data itself but only the model transforming datafor transforming the three-dimensional map display models is stored inthe map storage medium provided in the car navigation system withrespect to the road area to be three-dimensionally displayed. That is tosay, data for three-dimensional display can be stored in a highlycompressed form in the map storage medium, resulted in an extremelyreduced amount of data. Further, when only the two-dimensional map datais stored in the map storage medium and the car navigation systemgenerates model transforming data on the basis of the two-dimensionalmap data, the amount of data additionally stored in the map storagemedium can be almost zero.

[0179] Moreover, the present invention can considerably simplify astructure for processing in the algorithm for generating thethree-dimensional image data on the basis of model transforming data(hereinafter referred to as a three-dimensional image data generatingalgorithm). This is because the three-dimensional image data generatingalgorithm does not have to perform all the steps for calculating andgenerating three-dimensional image data, but it performs only thecomputation for transforming the previously defined three-dimensionalmap display models.

[0180] It is noted that the basic idea was described above only tofacilitate understanding of the present invention, and it should not beused to improperly limit the scope of the invention.

Description of the Specific Embodiments

[0181]FIG. 1 is a block diagram showing the structure of a modeltransforming data creating device of an embodiment of the presentinvention. In FIG. 1, the model transforming data creating device 1 ofthis embodiment includes an input portion 2, a two-dimensional map datastorage portion 3, a model transforming data generating portion 4, apattern model storage portion 5, an image data generating portion 6, adisplay 7, and a model transforming data storage portion 8.

[0182] The input portion 2 includes a cross-shaped pad, a mouse, akeyboard, and the like, which is operated by an operator to enter themap number, information for specifying a road area to bethree-dimensionally displayed, data for correcting parameters, patternnumber of a pattern model, and the like. The two-dimensional map datastorage portion 3 is composed of a large-capacity storage devicecontaining a storage medium such as a CD-ROM or DVD, which is used tostore two-dimensional map data. The model transforming data generatingportion 4 generates model transforming data required when transformingthe three-dimensional map display model on the basis of informationentered from the input portion 2, two-dimensional map data read out fromthe two-dimensional map data storage portion 3, and pattern data readout from the pattern model storage portion 5. The pattern model storageportion 5 contains pattern data defining sorts of parameters requiredwhen transforming each three-dimensional map display model. The imagedata generating portion 6 contains a three-dimensional image datagenerating algorithm, which generates three-dimensional image data onthe basis of the model transforming data generated in the modeltransforming data generating portion 4. The display 7 displaysthree-dimensional configuration of a specified road area on the basis ofthe three-dimensional image data generated in the image data generatingportion 6. The model transforming data storage portion 8 is used tostore model transforming data generated in the model transforming datagenerating portion 4.

[0183]FIG. 2 is a block diagram showing the details of the structure ofthe model transforming data generating portion 4 shown in FIG. 1. InFIG. 2, the model transforming data generating portion 4 includes atwo-dimensional map data reading portion 41, a parameter data extractingportion 42, and a parameter data analyzing portion 43.

[0184] The two-dimensional map data reading portion 41 readstwo-dimensional map data for an area corresponding to a map numberentered from the input portion 2 from the two-dimensional map datastorage portion 3. The parameter data extracting portion 42 extractsparameter data indicating attributes of each link from thetwo-dimensional map data read by the two-dimensional map data readingportion 41. The parameter data analyzing portion 43 analyzes theparameter data extracted by the parameter data extracting portion 42 andreads required pattern data from the pattern model storage portion 5 andgenerates the model transforming data for transforming thethree-dimensional map display model.

[0185] The model transforming data generated in the parameter dataanalyzing portion 43 is given to the image data generating portion 6 andconverted into three-dimensional image data, and the display 7 displaysthe corresponding three-dimensional configuration. The operator checksthe contents displayed on the display 7 to see whether a correctthree-dimensional image is displayed. When the three-dimensional imageis to be corrected, parameters for change or addition are entered fromthe input portion 2. This changes the contents of the model transformingdata generated in the parameter data analyzing portion 43 and thedisplayed contents on the display 7 change accordingly. When thethree-dimensional image displayed on the display 7 has been changed tothe form desired by the operator, the model transforming data generatedin the parameter data analyzing portion 43 is stored in the modeltransforming data storage portion 8.

[0186]FIG. 3 is a block diagram showing the greater details of thestructure of the parameter data analyzing portion 43 shown in FIG. 2. InFIG. 3, the parameter data analyzing portion 43 includes a patterndetermining portion 431, a parameter data classifying portion 432, adata integrating portion 433, and a data converting portion 434.

[0187] The pattern determining portion 431 determines a pattern of roadconfiguration to be adopted, on the basis of the parameter data on theroad area extracted by the parameter data extracting portion 42. Theparameter data classifying portion 432 classifies the parameter data ofeach road area on the basis of the pattern determined by the patterndetermining portion 431, in accordance with characteristic parts of theintersection pattern, such as elevated road, side pass, etc. The dataintegrating portion 433 integrates the parameter data classifiedaccording to the road function by the parameter data classifying portion432 for each road function to generate normalized parameter data. Theparameter data classifying portion 432 and the data integrating portion433 form a normalizing portion 430 for normalizing the parameter data.The data converting portion 434 converts the normalized parameter dataoutputted from the data integrating portion 433 into model transformingdata on the basis of the pattern data read out from the pattern modelstorage portion 5.

[0188] For more details of the structure of the pattern determiningportion 431, the pattern determining portion 431 includes a branchingarea road attribute deciding portion 4311 and a branch type decidingportion 4312. The branching area road attribute deciding portion 4311decides attributes of all roads connected to a branching point on thebasis of the parameter data extracted by the parameter data extractingportion 42. The attribute of roads represents the height of the roadsfrom the ground, which shows the configuration of the object road, i.e.,elevated road, underpass, or a road on the ground. The branch typedeciding portion 4312 detects a combination of the attributes of theroads connected to the branching point on the basis of the attributes ofthe roads decided by the branching area road attribute deciding portion4311 to determine the type of the branching. The branch type decidingportion 4312 then decides a pattern of the three-dimensional map displaymodel to be used from the determined type of the branching and outputs acorresponding pattern number.

[0189] For the details of the structure of the parameter dataclassifying portion 432, the parameter data classifying portion 432includes a link tracing portion 4321 and a link data classifying portion4322. The link tracing portion 4321 traces a two-dimensional map networkon the basis of the parameter data extracted by the parameter dataextracting portion 42. When tracing the map network, link data of thethree-dimensioned area is stored by utilizing the attribute, type,angle, area, and the like in the map data as criteria. The link dataclassifying portion 4322 classifies the link data stored in the linktracing portion 4321 for each road area and associates each part of thethree-dimensional map display model and the two-dimensional map network.

[0190]FIG. 4 is a flowchart showing the entire operation of the modeltransforming data creating device 1 shown in FIGS. 1 to 3. Referring toFIG. 4, the operation of the model transforming data creating device 1will now be described.

[0191] First, a map number including a road area to bethree-dimensionally displayed is entered to the model transforming datagenerating portion 4 from the input portion 2 (step S1). This embodimentadopts DRMA (Digital Road Map) for a format of the two-dimensional mapdata stored in the two-dimensional map data storage portion 3. In theDRMA, a map of the whole country is divided into a plurality of areasaccording to a given unit (e.g., secondary mesh unit). Thetwo-dimensional map data reading portion 41 in the model transformingdata generating portion 4 reads out the two-dimensional map data for anarea corresponding to the map number entered from the input portion 2,from the two-dimensional map data storage portion 3 (step S2).

[0192] Next, the model transforming data generating portion 4 specifiesa road area (e.g., a multi-level intersection) to be three-dimensionallydisplayed from the two-dimensional map data read out from thetwo-dimensional map data storage portion 3 (step S3). The operation ofspecifying the road area may be performed on the basis of specifyingdata entered from the input portion 2 (the former case) or may beperformed according to an algorithm for automatically specifying theroad area (the latter case). In the former case, the image datagenerating portion 6 creates image data on the two-dimensional mapcorresponding to the two-dimensional map data read out from thetwo-dimensional map data storage portion 3 and displays it on thedisplay 7. The operator draws a box, for example, around a part to bedisplayed in a three-dimensional manner on the two-dimensional map (orenlarged map thereof) displayed on the display 7 so as to specify a roadarea. At this time, the input portion 2 outputs specifying dataindicating the road area specified by the operator to the modeltransforming data generating portion 4. In response, the parameter dataextracting portion 42 in the model transforming data generating portion4 extracts parameter data for the area corresponding to the specifyingdata entered from the input portion 2 from the two-dimensional map data(step S4). In the latter case, the parameter data extracting portion 42in the model transforming data generating portion 4 searches for a roadarea conforming with previously set conditions on the two-dimensionalmap data read from the two-dimensional map data storage means 3 andextracts the parameter data in the vicinity of the found road area(e.g., in the area within a 500-m radius) from the two-dimensional mapdata (step S4).

[0193]FIG. 5 shows an example of the parameter data extracted from thetwo-dimensional map data in step S4. In FIG. 5, the vertically listednumbers 1 to 23 correspond to 23 roads (hereinafter referred to aslinks). For example, it shows that the link 1 has a length of 20 m andfour lanes, and its link attribute shows that it is a part of anordinary-type road. Further, since bidirectional passage is permitted,it is known that the four lanes include two lanes for one direction andtwo lanes for the opposite direction. It also shows that the link 4 hasa length of 20 m and two lanes, and its link attribute shows that it isan elevated road. Accordingly it is known that information for avertical direction must be provided for the link 4. It shows that thelink 7 has a length of 5 m and one lane, and its link attribute shows aside pass. Further, the link 17 has a length of 5 m and two lanes, andits link attribute shows an underpass (a road running under an elevatedroad). The map parameters shown in FIG. 5 can be visualized as atwo-dimensional map as shown in FIG. 6.

[0194] While this embodiment adopts DRMA for a format of thetwo-dimensional map data stored in the two-dimensional map data storageportion 3 as stated above, two-dimensional map data described in anothermap data format may be stored in the two-dimensional map data storageportion 3. When some data is wanting, e.g. information contained in DRMAbut not in another map data format (e.g., information about the numberof lanes), or information contained in another map data format but notin DRMA, it will be separately entered from the input portion 2.

[0195] Next, the pattern determining portion 431 analyzes parameter dataextracted by the parameter data extracting portion 42 to determine towhich patterns of intersection configuration previously classified thethree-dimensional configuration of the target road area belongs (stepS5). FIG. 7 shows the details of this subroutine step S5.

[0196] Referring to FIG. 7, the branching area road attribute decidingportion 4311 checks, first of all, all the roads connecting to the pointrequired to be navigated (e.g., a branching point between a main roadand a side pass) on the basis of the parameter data extracted by theparameter data extracting portion 42 to decide each attribute thereof;elevated road, underpass, or road on the ground (step S51). Second, thebranch type deciding portion 4312 decides the type of the branching onthe basis of the attributes of the connected roads decided by thebranching area road attribute deciding portion 4311 (step S52). Thebranch type may contain, as shown in FIG. 8, case (a) in which a road onthe ground branches out into an elevated road and a side pass, case (b)in which a road on the ground branches out into an underpass and a sidepass, and case (c) in which an elevated road branches out into anelevated road and a side pass. It then decides a three-dimensional mapdisplay model pattern to be used on the basis of the determined type ofthe branching (step S53). This decision may be made by the operator, inwhich case a pattern number is entered into the parameter data analyzingportion 43 from the input portion 2. For the three-dimensional mapdisplay model patterns, for example, the case (a) of a road on theground branching out into an elevated road and a side pass maycorrespond to the three-dimensional map display model pattern shown inFIG. 9, the case (b) of a road on the ground branching out into anunderpass and a side pass may correspond to the three-dimensional mapdisplay model pattern shown in FIG. 10, and the case (c) of an elevatedroad branching out into an elevated road and a side pass may correspondto the three-dimensional map display model pattern shown in FIG. 11.Further, the branch type deciding portion 4312 gives a pattern numbercorresponding to the determined or entered pattern to the pattern modelstorage portion 5 to read out the pattern data corresponding to thedetermined or entered pattern from the pattern model storage portion 5.As stated above, the pattern model storage portion 5 contains patterndata for defining types of parameters required to transform eachthree-dimensional map display model. FIG. 12 shows an example of thepattern data stored in the pattern model storage portion 5. As shown inFIG. 12, the pattern data is prepared as blank table data in whichparameters are to be set.

[0197] Referring to the main routine of FIG. 4 again, the parameter dataclassifying portion 432 classifies the two-dimensional parameter dataextracted by the parameter data extracting portion 42 according to theirrespective road functions, on the basis of the pattern determined in thepattern determining portion 431 (step S6). In the data classification,for example, a multi-level intersection may be classified into a roadnot on the ground for a part of the multi-level intersection, a sidepass to make a right/left turn, and an approach. The road functions maybe classified on the basis of the configuration of intersections in thisway; in another method, a series of roads existing between adjacentbranching points, or between adjacent merging points, or betweenadjacent branching point and merging point, may be classified as a groupof roads having the same function.

[0198]FIG. 13 shows an example of the two-dimensional parameter dataclassified according to the road function. The data shown in FIG. 5 areused as the classified data. In FIG. 13, the vertically listed numbers 1to 10 correspond to ten roads differing in function. For example, thelink Nos.1 to 3 are data of the same road function, which are classifiedas the road No.1; similarly, the link Nos.4 and 5 are classified as theroad No.2, link No.6 as road No.3, link Nos.7 and 8 as road No.4, linkNo.9 as road No.5, link Nos.10 to 12 as road No.6, link Nos.13 and 14 asroad No.7, link Nos.15 and 16 as road No.8, link Nos.17 to 19 as roadNo.9, and link Nos.20 to 23 as road No.10.

[0199]FIG. 14 shows the greater details of the above-described operationin the subroutine step S6. Referring to FIG. 14, first, the link tracingportion 4321 traces links in the three-dimensioned area on the basis ofthe parameter data extracted by the parameter data extracting portion 42and temporarily holds the links required to generate a three-dimensionalmap display model (step S61). FIG. 15 shows an example of thetwo-dimensional map, FIG. 16 shows an example of results of the trace oflinks, and FIG. 17 shows an example of results of storage of the data oftraced links. The criterion in tracing links may include an attribute,type, angle, area, and the like. Next, the link data classifying portion4322 classifies the link data held in the link tracing portion 4321according to the road function (step S62). The road function may includean approach to a branching point, elevated road from the branchingpoint, and side pass from the branching point; the link data areclassified into roads having the same function. FIG. 18 shows an exampleof links classified according to the road function.

[0200] Referring to the main routine of FIG. 4 again, the dataintegrating portion 433 integrates the parameter data classified in theparameter data classifying portion 432 (step S7). The data integrationmeans the operation of integrating the data classified according to roadfunction into one road. This data integrating operation may be achievedby a method of selecting arbitrary data from the plurality of dataclassified according to road function and adopting the data asrepresentative of the roads in that part, or a method of calculating anaverage value of the plurality of data classified according to roadfunction and adopting the average value as the road in that part.

[0201]FIG. 19 shows an example of parameter data created by integratingdata for each road function. The data classified in FIG. 13 are used asthe integrated data. For example, while the parameter data correspondingto the road No.1 is regarded as a group of three link data in FIG. 13,the three link data are integrated into one road in FIG. 19. Similarly,the data classified according to road numbers are integrated into one.

[0202] The map parameters shown in FIG. 19 can be visualized as atwo-dimensional map as shown in FIG. 20. Although FIG. 20 istwo-dimensionally represented, it substantially shows an example ofintersection pattern prepared as a three-dimensional map display model.In FIG. 20, the types of hatching applied to the road parts 1 to 10represent the road functions classified in the pattern. Morespecifically, the road parts 2 and 9 belong to a road not on the ground(elevated road or underpass), the road parts 4 to 7 belong to a sidepass, and the road parts 1, 3, 8 and 10 belong to an approach. Theparameters of FIG. 19, which have been generated as the result ofclassification and integration, correspond to the road parts shown inFIG. 20, where the road Nos.1 to 10 in FIG. 19 correspond to the roadparts 1 to 10 in FIG. 20, respectively. When the configuration of theprepared intersection pattern differs from that of FIG. 20, a structureintegrated according to the pattern configuration is changed inparameter data generated as shown in FIG. 19. The parameter dataintegrated in the data integrating portion 433 is given to the dataconverting portion 434 as normalized parameter data.

[0203] Next, the data converting portion 434 converts the parameter datagiven from the data integrating portion 433 into model transforming dataon the basis of the pattern data read out from the pattern model storageportion 5 (step S8). The operation of the data converting portion 434will be described in greater detail below.

[0204] Among the parameter data normalized in the normalizing portion430, the data converting portion 434 first sets parameter data which canbe simply transferred, into the pattern data read out from the patternmodel storage means 6. FIG. 21 shows an example of the pattern data inwhich the parameters are set. Referring to FIG. 21, the data convertingportion 434 sets the parameter showing length and the parameter showingthe number of lanes in the pattern data, as the parameter data which cansimply be transferred. The parameter showing the number of lanes is setas the parameter showing the width of road.

[0205] Next, the data converting portion 434 analyzes the parameter datanormalized in the normalizing portion 430 to infer values of other unsetparameters in the pattern data. For example, since the link 2 is anelevated road and the link 9 is an underpass, it infers that the tworoads intersect each other with the link 2 located in the higher level.Accordingly a height flag 1 is set to the link 2 in the pattern data,and a height flag 0 is set to the link 9. A height flag with a largernumber indicates a higher position. When the angle of the intersectionof link 2 and link 9 can be calculated from the normalized parameterdata, the calculated intersecting angle is set in the pattern data.Usually, DRMA shows the coordinate positions of links, and theintersecting angles can be calculated from the coordinate positions. Thedata converting portion 434 also infers the configuration of links andsets the result in the pattern data as the parameter showing theconfiguration pattern. The configurations of links are classified intosome categories. For example, the first category shown in FIG. 22 (acategory showing the shape of ordinary-type roads), the second categoryshown in FIG. 23 (a category showing the shape of elevated roads), andthe third category shown in FIG. 24 (a category showing how the roadsare connected at branching/merging points) are included. At this time,in the simplest method for inferring a shape of ordinary-type roads, theshapes of the roads in the whole country are collected so as to decidewhich shape is the most popular for links of the determined pattern, andthen the most popular shape among the roads is set for a shape of therespective link. It is possible to infer how an elevated road isconfigured, or how roads are connected to one another at abranching/merging point from the relation among interconnected links inthe neighborhood.

[0206] Parameters not specified by inference may be left unset, or someparameters may be temporarily set. When parameters are not set, theconfiguration of the links is displayed according to the configurationof a standard three-dimensional map display model buried in thethree-dimensional image data generating algorithm executed by the imagedata generating portion 6. However, there is no problem in thisembodiment because the parameters can be corrected later by theoperator.

[0207] Next, the data converting portion 434 outputs the pattern data inwhich the parameters are set to the image data generating portion 6 asmodel transforming data. The image data generating portion 6 generatesthree-dimensional image data on the basis of the model transformingdata, and outputs it to the display 7 (step S9). In response, thedisplay 7 displays a three-dimensional map. The image data generatingportion 6 can achieve the calculation by just transforming a previouslydefined three-dimensional map display model with the model transformingdata, instead of performing all the calculations for generating thethree-dimensional image data. Accordingly the three-dimensional imagedata generating algorithm in the image data generating portion 6 can beconsiderably simplified as compared with the conventional algorithmwhich processes two-dimensional map data with added width and heightinformation as three-dimensional coordinate data to generate thethree-dimensional polygon data. This effect can be obtained similarlyalso in the three-dimensional map display performed later in the carnavigation system carried on a vehicle. The amount of calculation forexecuting the simplified three-dimensional image data generatingalgorithm is greatly reduced, which enables smooth map scrolling. Thedetailed structure and operation of the image data generating portion 6will be described later.

[0208] Next, the operator checks the contents displayed in the display 7to see whether a correct three-dimensional image is displayed (stepS10). When the three-dimensional image should be corrected, parametersfor change or addition are entered from the input portion 2 (step S11).This changes the contents of the model transforming data generated inthe parameter data analyzing portion 43 and the contents displayed inthe display 7 also changes accordingly. When the three-dimensional imagedisplayed in the display 7 has been changed to satisfy the operator, themodel transforming data generated in the parameter data analyzingportion 43 is outputted to and stored in the model transforming datastorage portion 8 (step S12). FIG. 25 shows an example of display of athree-dimensional map corresponding to the model transforming data shownin FIG. 21.

[0209] When a large number of areas are specified for three-dimensionaldisplay in step S3 of FIG. 4 in the above embodiment, the modeltransforming data can be generated for all roads on the map, and thenthe car navigation system can three-dimensionally display all the roadsunder car-navigation.

[0210] Further, in the present invention, in order to improve theefficiency in the process of creating model transforming data and theprocess of generating the three-dimensional image data, and also inorder to improve the quality of the created three-dimensional map data,the three-dimensional map may be created and displayed according topatterns having a hierarchical structure called a macro/micro pattern.The macro pattern handles a mass of models required in navigation as asingle pattern; for example, FIGS. 9 to 11 show three-dimensional mapdisplay models corresponding to the macro patterns of typicalmulti-level intersection configurations. For example, FIG. 9 shows atypical multi-level intersection model, which is composed of an approachroad reaching a branching point, a side pass, and an elevated road.However, when three-dimensional map display models are created only withthe macro pattern models, multi-level intersections not conforming withthe patterns cannot be represented, and the number of patterns increasesin steps depending on the number of sampling data for the objectintersections to be three-dimensionally displayed. Moreover, there is aproblem that independently developing different macro patterns reducesexpandability and reusability in the future. Accordingly, for thepurpose of compensating for the disadvantages of the macro pattern andexpanding the three-dimensional display to all roads, the micro patternsystem is used together with it to create the three-dimensional mapdisplay models. The micro pattern means a unit of pattern, such as theroad shape primitive patterns shown in FIG. 22, elevated road shapeprimitive patterns as shown in FIG. 23, and patterns for connectingprimitive patterns as shown in FIG. 24 (branching, merging,intersecting, and the like.); the micro patterns are combined to form athree-dimensional map display model. That is to say, to improve theefficiency in creating the model transforming parameters, and also tonormalize the created model for better appearance, typical multi-levelintersections are three-dimensioned by using macro patterns showingintersection structures hierarchically structured according toexperiential knowledge, and parts not conforming with the structure arethree-dimensionally represented by using the micro patterns. However, adesired three-dimensional map display model can be created merely bycombining micro patterns, without using the macro pattern.

[0211]FIG. 26 is a block diagram showing the greater details of theimage data generating portion 6 shown in FIG. 1. In FIG. 26, thethree-dimensional data generating portion 6 includes a three-dimensionalpolygon data generating portion 61, a rendering portion 62, athree-dimensional polygon data storage portion 63, and athree-dimensional image data storage portion 64.

[0212] The three-dimensional polygon data generating portion 61generates three-dimensional polygon data on the basis of the modeltransforming data provided from the model transforming data generatingportion 4. The generated three-dimensional polygon data is stored in thethree-dimensional polygon data storage portion 63 and is also providedto the rendering portion 62. The rendering portion 62 generatesthree-dimensional image data on the basis of the three-dimensionalpolygon data generated in the three-dimensional polygon data generatingportion 61. The generated three-dimensional image data is stored in thethree-dimensional image data storage portion 64 and is also provided tothe display 7.

[0213]FIG. 27 is a block diagram showing the greater details of thethree-dimensional polygon data generating portion 61 shown in FIG. 26.In FIG. 27, the three-dimensional polygon data generating portion 61includes a model transforming data analyzing portion 611, athree-dimensional polygon data synthesizing portion 612, a configurationattribute storage portion 613, and a three-dimensional polygon library614.

[0214] The model transforming data analyzing portion 611 analyzes theparameter data generated by the model transforming data generatingportion 4 for each road area to select a three-dimensional map displaymodel corresponding to the pattern of the road configuration as shown inFIG. 23 and to extract parameter values of the road length, road width,and the like.

[0215] The configuration attribute storage portion 613 is used to storeparameters for more finely transforming the road configuration patternmodel corresponding to the three-dimensional map display model, whichcontains parameter values for the color and material of roads, spacingand number of bridge girders attached to elevated roads, width ofshoulders, height of sound-proof walls, and the like, for example.

[0216]FIG. 28 shows an example of contents of parameters and theirdefault values stored in the configuration attribute storage portion613. In FIG. 28, byway of example,the configuration attribute storageportion 613 contains parameters about the spacing between supports(girders) of elevated road, parameters about safety walls (placementoffset, width and height of safety walls), parameters about trafficlights (the file name of the polygon library containing polygon dataabout traffic lights, height and scale factor, and type of trafficlights), parameters about background (the name of the file containingtexture material images used for background), parameters about the sizeof the three-dimensional model world (width, length and thickness of theground in the three-dimensional model world, coordinate values of thehorizon), parameters about the color of roads, parameters about thecolor of elevated roads, parameters about the color of safety walls,parameters about the color of supports, parameters about roads(thickness of roads, width of one lane), and parameters about elevatedroads (height, h, of one level, grade of first section 11, grade ofsecond section 12, grade of third section 13).

[0217] The three-dimensional polygon library 614 contains polygon datafor accessories attached to the three-dimensional map, such as trafficlights and various landmarks (banks, shops, schools, etc.).

[0218] The three-dimensional polygon data synthesizing portion 612creates corresponding three-dimensional polygon data by referring to thedata analyzed in the model transforming data analyzing portion 611,various parameters stored in the configuration attribute storage portion613, and polygon data stored in the three-dimensional polygon library614.

[0219]FIG. 29 is a flowchart showing the operation of thethree-dimensional polygon data generating portion 61 shown in FIG. 26.Referring to FIG. 29, the operation of the three-dimensional polygondata generating portion 61 will now be described.

[0220] First, the model transforming data corresponding to the road areato be three-dimensionally displayed is inputted from the modeltransforming data generating portion 4 into the three-dimensionalpolygon data generating portion 61 (step S101). In response, the modeltransforming data analyzing portion 611 analyzes the input modeltransforming data and selects a three-dimensional map display modelcorresponding to such road configuration pattern as shown in FIG. 23 andextracts parameter values about the road length, road width, etc. (stepS102). Next, the three-dimensional polygon data synthesizing portion 612reads default values for various parameters stored in the configurationattribute storage portion 613 (refer to FIG. 28) and also reads thepolygon data for traffic lights and landmarks stored in thethree-dimensional polygon library 614 (step S103). Then thethree-dimensional polygon data synthesizing portion 612 calculates thethree-dimensional coordinates by referring to the data analyzed in themodel transforming data analyzing portion 611, various parameters storedin the configuration attribute storage portion 613, and polygon datastored in the three-dimensional polygon library 614, to createthree-dimensional polygon data (step S104). The createdthree-dimensional polygon data is provided to the rendering portion 62.

[0221] The operation of the three-dimensional polygon data generatingportion 61 will now be described with more specific examples.

[0222] First, the operation performed when the model transforming dataof the link No.1 in FIG. 21 is provided to the three-dimensional polygondata generating portion 61 will be described. As shown in FIG. 30, whenthe model transforming data about the link No.1 is provided to the modeltransforming data analyzing portion 611, the model transforming dataanalyzing portion 611 extracts the following parameters from the modeltransforming data:

[0223] Link No.=1

[0224] Length=50

[0225] Width=4

[0226] Road shape=1

[0227] Elevated road shape=no definition

[0228] Connection shape=1 a

[0229] Height=no definition

[0230] Since the extracted parameters do not define the elevated roadshape nor height, it is known that the road corresponding to this linkis a road on the ground having no supports for elevated road. At thistime, as shown in FIG. 22(1), since the road shape=1 corresponds to alinear road shape, the model transforming data analyzing portion 611selects function FUNC1 for generating a rectangular prism polygon fromthe width, length and thickness, and sets the parameter values extractedfrom the model transforming data in the selected function FUNC1 (in thiscase, length=50, width=4). The function FUNC1 with the set parametervalues is provided to the three-dimensional polygon data synthesizingportion 612.

[0231] Receiving the function FUNC1 from the model transforming dataanalyzing portion 611, the three-dimensional polygon data synthesizingportion 612 reads configuration attribute information required for thefunction FUNC1 (in this case, color of road=gray, thickness of road=0.5,width of road=3.5) from the configuration attribute information storedin the configuration attribute storage portion 613 (see FIG. 28).

[0232] The outline of the processing of the function FUNC1 will now bedescribed referring to FIG. 32. FIG. 33 shows an image diagram of thethree-dimensional polygon data generated in the function FUNC1. Thepolygon shown in FIG. 33 has the eight vertexes (a, b, c, d, e, f, g,h). Then the coordinates of the vertexes and the list of vertexesdefining the faces can be represented by the following combinations ofparameters, by calculating with length=l, width=w, and thickness=dep andusing the vertex “a” as the origin:

[0233] a=(0, 0, 0)

[0234] b=(0, l, 0)

[0235] c=(w, l, 0)

[0236] d=(w, 0, 0)

[0237] e=(0, 0, dep)

[0238] f=(0, l, dep)

[0239] g=(w, l, dep)

[0240] h=(w, 0, dep)

[0241] The structure of the face list can be represented by thefollowing vertex list:

[0242] f1=(a, b, c, d)

[0243] f2=(d, c, g, h)

[0244] f3=(h, g, f, e)

[0245] f4=(e, f, b, a)

[0246] f5=(a, d, h, e)

[0247] f6=(b, c, g, f)

[0248] Then the three-dimensional polygon data synthesizing portion 612applies w=14, 1=50, and dep=0.5 to the functions to calculate values ofthe vertexes. The calculation provides the following results:

[0249] a=(0, 0, 0)

[0250] b=(0, 50, 0)

[0251] c=(14, 50, 0)

[0252] d=(14, 0, 0)

[0253] e=(0, 0, 0.5)

[0254] f=(0, 50, 0.5)

[0255] g=(14, 50, 0.5)

[0256] h=(14, 0, 0.5)

[0257] Further, since the road texture=gray, the material is set as (R,G, B)=(0.2, 0.2, 0.2). For the RGB value, the RGB default value defininggray is referred to. The road texture may be defined for each face, orone texture may be defined for one road. The three-dimensional polygondata 1 thus calculated is provided to the rendering portion 62 as thethree-dimensional polygon data 1 as shown in FIG. 32.

[0258] Next, the operation performed when the model transforming data ofthe link No.4 in FIG. 21 is provided to the three-dimensional polygondata generating portion 61 will now be described. As shown in FIG. 30,when the model transforming data of link No.4 is provided to the modeltransforming data analyzing portion 611, the model transforming dataanalyzing portion 611 extracts the following parameters from the modeltransforming data:

[0259] Link No.=4

[0260] Length=10

[0261] Width=1

[0262] Road shape=1

[0263] Elevated road shape=1

[0264] Connection shape=1 d

[0265] Height=no definition

[0266] Since the extracted parameters define the shape of elevated road,it is known that the road corresponding to this link is a road not onthe ground. At this time, as shown in FIG. 22 (1), since the roadshape=1 corresponds to the linear road shape, the model transformingdata analyzing portion 611 selects function FUNCB1 for generating anelevated-road type polygon only from the width, length, and thickness,and sets the parameter values extracted from the model transforming datain the selected function FUNCB1 (in this case, length=10, width=1). Thefunction FUNCB1 with the set parameter values is provided to thethree-dimensional polygon data synthesizing portion 612.

[0267] Receiving the function FUNCB1 from the model transforming dataanalyzing portion 611, the three-dimensional polygon data synthesizingportion 612 reads configuration attribute information required for thefunction FUNCB1 (in this case, color of road=gray, thickness ofroad=0.5, width of road=3.5, h=3, l1=2, l2=6, l3=2) from theconfiguration attribute information stored in the configurationattribute storage portion 613 (see FIG. 28).

[0268] The outline of the processing of the function FUNCB1 will now bedescribed referring to FIGS. 34 and 35. FIG. 36 shows an image diagramof the three-dimensional polygon data generated in the function FUNCB1.The polygon shown in FIG. 36 has the 16 vertexes (1, 2, 3, 4, 5, 6, 7,8, 9, 10, 11, 12, 13, 14, 15, 16). Then the coordinates of the vertexesand the list of vertexes defining the faces can be represented by thefollowing combinations of parameters, by calculating with length=l,width=w, and thickness=dep, and elevated-road parameter height=h, firstsection grade=l1, second section grade=l2, third section grade=13, andusing the vertex 1 as the origin:

[0269]1=(0, 0, 0)

[0270]2=(0, l1, h)

[0271]3=(0, l1+l2, h)

[0272]4=(0, l, 0)

[0273]5=(0, 0, -dep)

[0274]6=(0, l1, h-dep)

[0275]7=(0, l1+l2, h-dep)

[0276]8=(0, l, -dep)

[0277]9=(w, 0, 0)

[0278]10=(w, l1, h)

[0279]11=(w, l1+l2, h)

[0280]12=(w, l, 0)

[0281]13=(w, 0, -dep)

[0282]14=(w, l1, h-dep)

[0283]15=(w, l1+l2, h-dep)

[0284]16=(w, l, -dep)

[0285] The structure of the face list can be represented by thefollowing vertex list:

[0286] f1=(1, 2, 10, 9)

[0287] f2=(2, 3, 11, 10)

[0288] f3=(3, 4, 12, 11)

[0289] f4=(9, 10, 14, 13)

[0290] f5=(10, 11, 15, 14)

[0291] f6=(11, 12, 16, 15)

[0292] f7=(5, 6, 14, 13)

[0293] f8=(6, 7, 15, 14)

[0294] f9=(7, 8, 16, 15)

[0295] f10=(1, 2, 6, 5)

[0296] f11=(2, 3, 7, 6)

[0297] f12=(3, 4, 8, 7)

[0298] f13=(1, 5, 13, 9)

[0299] f14=(4, 8, 16, 12)

[0300] Then the three-dimensional polygon data synthesizing portion 612applies w=3.5, 1=10, dep=0.5, l1=2, l2=6, l3=2, h=3 to the functions tocalculate the values of the vertexes. The calculation results asfollows:

[0301]1=(0, 0, 0)

[0302]2=(0, 2, 3)

[0303]3=(0, 4, 3)

[0304]4=(0, 10, 0)

[0305]5=(0, 0, −0.5)

[0306]6=(0, 2, 2.5)

[0307]7=(0, 4, 2.5)

[0308]8=(0, 10, −0.5)

[0309]9=(3.5, 0, 0)

[0310]10=(3.5, 2, 3)

[0311]11=(3.5, 4, 3)

[0312]12=(3.5, 10, 0)

[0313]13=(3.5, 0, −0.5)

[0314]14=(3.5, 2, 2.5)

[0315]15=(3.5, 4, 2.5)

[0316]16=(3.5, 10, −0.5)

[0317] Further, since the elevated-road texture=gray, the material isset as (R, G, B)=(0.2, 0.2, 0.2) . For the RGB value, the RGB defaultvalue defining gray is referred to. The elevated-road texture may bedefined for each face, or one texture may be defined for one elevatedroad. The three-dimensional polygon data B1 thus calculated is providedto the rendering portion 62 as the three-dimensional polygon data B1 asshown in FIG. 35.

[0318] The three-dimensional polygon data generating portion 61 repeatsthe above-described series of processes for the number of the modeltransforming data. While the three-dimensionally polygon synthesizedcoordinate values are described about the origin to simply describe theflow of processing, the adjustment of the coordinate values isre-calculated on the basis of the connecting configuration pattern andintersecting angle values in the model transforming data.

[0319] The model transforming data are created for a plurality of roadareas as described above and stored in the model transforming datastorage portion 8. After that, preferably, the model transforming datastored in the model transforming data storage portion 8 are stored inthe same storage medium together with the two-dimensional map datastored in the two-dimensional map data storage portion 3. At this time,the correspondence between the model transforming data and thetwo-dimensional map data is also described in the storage medium. Thestorage medium is then set in a car navigation system carried on avehicle and used for navigation. That is to say, the car navigationsystem has a three-dimensional image data generating algorithmequivalent to step S9 in FIG. 4, and when the vehicle comes closer to aroad area to be three-dimensionally displayed, the three-dimensionalimage data generating algorithm reads out a model transforming datacorresponding to the road area, gives it to the correspondingthree-dimensional map display model and transforms it, and thusgenerates and displays the desired three-dimensional image data.

[0320] The model transforming data obtained in the above-described waycan be applied not only to a navigation system for a vehicle but also toa drive simulator operating on a personal computer and to a portablenavigation system carried by a man.

[0321] Although the model transforming data created by the modeltransforming data creating device is stored in a storage medium and usedin a car navigation system in the above-described embodiment,three-dimensional polygon data stored in the three-dimensional polygondata storage portion 63 or three-dimensional image data stored in thethree-dimensional image data storage portion 64 may be stored in the mapstorage medium in place of the model transforming data and used in thecar navigation system. In this case, the processing load on the carnavigation system is reduced for it does not perform the calculation fortransforming the three-dimensional map display models, but the amount ofdata stored in the map storage medium is increased.

[0322]FIG. 37 is a block diagram showing the structure of a navigationsystem according to an embodiment of the present invention. In FIG. 37,the navigation system of this embodiment includes an input portion 10, aposition detecting portion 11, a map data storage portion 13, a routeselecting portion 12, a navigating portion 14, and an output portion 15.

[0323] The input portion 10 includes a remote controller, a touchsensor, a keyboard, a mouse, and the like, which is used to selectfunctions of the navigation system (to change the processed item, changethe map, change the hierarchical level, etc.) and also to set a point,select the search mode, and the like. The position detecting portion 11includes a GPS, a car-velocity sensor, an angular velocity sensor, anabsolute direction sensor, and the like, which is used to detect thecurrent position of the vehicle. The map data storage portion 13 iscomposed of an optical disk (CD, DVD, etc.), a hard disk, alarge-capacity memory, and the like, in which the two-dimensional mapdata is stored. The route selecting portion 12 reads the map data of anobject area from the map data storage portion 13, determines thestarting point and destination on the basis of the current position ofthe vehicle detected by the position detecting portion 11 and pointinformation entered from the input portion 10, and selects the smallestcost route from the starting point to the destination (the shortest-timeroute or the shortest-distance route) while considering trafficregulations at intersections and one-way traffic regulations. Thenavigating portion 14 generates information on navigation for directingthe vehicle to reach the destination according to the navigated routeselected by the route selecting portion 12 on the basis of the map dataobtained from the map data storage portion 13 and the current positionof the vehicle detected by the position detecting portion 11. Thenavigation performed here may be realized with map display, with voice,and the like. The output portion 15 includes a display device(liquid-crystal display, CRT display, etc.), a speaker, etc., whichdisplays information on navigation generated in the navigating portion14 and/or outputs it in audio.

[0324]FIG. 38 is a block diagram showing the greater details of thestructure of the navigating portion 14 of FIG. 37. In FIG. 38, thenavigating portion 14 includes a three-dimensional map display decisionportion 141, a two-dimensional map display portion 142, and athree-dimensional map display portion 143.

[0325] The three-dimensional map display decision portion 141 decideswhether to display a three-dimensional map on the basis of the vehicleposition data generated in the position detecting portion 11, the routedata generated in the route selecting portion 12, and thetwo-dimensional map data stored in the map data storage portion 13.After receiving the decision of not displaying a three-dimensional mapfrom the three-dimensional map display decision portion 141, thetwo-dimensional map display portion 142 generates two-dimensional mapdisplay data on the basis of the vehicle position data generated in theposition detecting portion 11, the route data generated in the routeselecting portion 12, and the two-dimensional map data stored in the mapdata storage portion 13. After receiving the decision of requiring athree-dimensional display from the three-dimensional map displaydecision portion 141, the three-dimensional map display portion 143generates three-dimensional map display data on the basis of the vehicleposition data generated in the position detecting portion 11, the routedata generated in the route selecting portion 12, and thetwo-dimensional map data stored in the map data storage portion 13.

[0326]FIG. 39 is a flowchart showing the operation of the navigatingportion 14 shown in FIG. 37. The operation of the navigating portion 14will now be described referring to FIG. 39.

[0327] First, the three-dimensional map display decision portion 141reads the two-dimensional map data about the area corresponding to thecurrent position detected in the position detecting portion 11 from themap data storage portion 13 and searches the read two-dimensional mapdata for a three-dimensional map display flag (step S301). Next, thethree-dimensional map display decision portion 141 determines whetherthere is a three-dimensional map display flag from the result of thesearch (step S302). When a three-dimensional map display flag is notcontained, the two-dimensional map display portion 142 generates thetwo-dimensional map display data (step S304). When a three-dimensionalmap display flag is contained, the three-dimensional map display portion143 generates the three-dimensional map display data (step S303).

[0328]FIG. 40 is a block diagram showing the structure of thethree-dimensional map display portion 143 shown in FIG. 38 in greaterdetail. In FIG. 40, the three-dimensional map display portion 143includes a model transforming data storage portion 1431, athree-dimensional polygon data generating portion 1432, and a renderingportion 1433.

[0329] The model transforming data storage portion 1431 is composed of alarge-capacity storage device containing a CD-ROM or DVD as a storagemedium, which contains the model transforming data created by the modeltransforming data creating device 1 shown in FIG. 1. Thethree-dimensional polygon data generating portion 1432 has the samestructure as the three-dimensional polygon data generating portion 61shown in FIG. 26, which generates three-dimensional polygon data on thebasis of the model transforming data stored in the model transformingdata storage portion 1431. That is to say, the three-dimensional polygondata generating portion 1432 reads the model transforming datacorresponding to the road area to be three-dimensionally displayed fromthe model transforming data storage portion 1431 and selects athree-dimensional map display model corresponding to the roadconfiguration pattern and extracts the parameter values about the roadlength, width, and the like. Then the three-dimensional polygon datagenerating portion 1432 sets the default values of parameters about thecolor and material of road, spacing and number of girders attached toelevated road, width of shoulders and height of sound-proof walls, andthe like, and also refers to the three-dimensional polygon library fortraffic lights and landmarks, and calculates the three-dimensionalcoordinates of the three-dimensional polygons to generate thethree-dimensional polygon data. The rendering portion 1433 has the samestructure as the rendering portion 62 shown in FIG. 26, which generatesthree-dimensional image data on the basis of the three-dimensionalpolygon data generated in the three-dimensional polygon data generatingportion 1432. The generated three-dimensional image data is given to theoutput portion 15.

[0330]FIG. 41 is a flowchart showing the operation of thethree-dimensional map display portion 143 shown in FIG. 40. Referring toFIG. 40, the operation of the three-dimensional map display portion 143will be described. First, the three-dimensional polygon data generatingportion 1432 reads model transforming data corresponding to thethree-dimensionally displayed road area from the model transforming datastorage portion 1431 (step S401), and analyzes the parameter data aboutthe road area and selects a three-dimensional map display modelcorresponding to the road configuration pattern, as shown in FIG. 23,and extracts parameter values about the road length, road width, and thelike. (step S402). Next, the three-dimensional polygon data generatingportion 1432 reads the default values of parameters about the color andmaterial of road, spacing and number of girders attached to elevatedroad, width of shoulders and height of sound-proof walls, and the like.,and it also reads polygon data about traffic lights and landmarks storedin the three-dimensional polygon library in the three-dimensionalpolygon data generating portion 1432 (step S403). Then thethree-dimensional polygon data generating portion 1431 calculates thethree-dimensional coordinates of the three-dimensional polygons byreferring to the information and data and thus creates thethree-dimensional polygon data (step S404). Next, the rendering portion1433 performs rendering on the basis of the three-dimensional polygondata created in step S404 to create the three-dimensional image data(step S405). Next, the rendering portion 1433 outputs the createdthree-dimensional image data to the output portion 15 (step S406).

[0331] While the model transforming data is fixedly stored in the modeltransforming data storage portion 1431 in the embodiment shown in FIG.40, a communication device 1434 may be added as shown in FIG. 42, inwhich case model transforming data transmitted from a center station(not shown) is received at the communication device 1434 and the modeltransforming data stored in the model transforming data storage portion1431 is updated in a real-time manner.

[0332]FIG. 43 is a block diagram showing another structure of thethree-dimensional map display portion 143 shown in FIG. 38. In FIG. 43,the three-dimensional map display portion 143 includes a modeltransforming data generating portion 1435, the three-dimensional polygondata generating portion 1432, and the rendering portion 1433.

[0333] The model transforming data generating portion 1431 has the samestructure as the model transforming data generating portion 4 and thepattern model storage portion 5 shown in FIG. 1, which generates modeltransforming data on the basis of the two-dimensional map data stored inthe map data storage portion 13. The three-dimensional polygon datagenerating portion 1432 generates three-dimensional polygon data on thebasis of the model transforming data generated in the model transformingdata generating portion 1431. The rendering portion 1433 performsrendering on the basis of the three-dimensional polygon data created inthe three-dimensional polygon data generating portion 1432 to create thethree-dimensional image data. While the processing load on thenavigation system is increased in this example since the modeltransforming data is generated in the navigation system, the amount ofdata stored inside is considerably reduced since the model transformingdata is not stored in advance.

Industrial Applicability

[0334] As described above, the model transforming data generated in thepresent invention can effectively be used when displaying athree-dimensional map in a car navigation system, and the like.

What is claimed is:
 1. A storage medium for use in a three-dimensionalmap display device in which a three-dimensional configuration of a givenpart on two-dimensional map data is classified in advance into aplurality of patterns and a transformable three-dimensional map displaymodel is prepared in advance for each of the patterns, and thethree-dimensional map display model is transformed into a desired formto generate and display three-dimensional image data of the given part,said storage medium comprising: model transforming data operable totransform the three-dimensional map display model into the desired formin correspondence with the given part to be three-dimensionallydisplayed.